Recent dramatic innovation on lithography techniques for patterning in the manufacture of semiconductor devices has made lithographic line widths finer and finer. In lithographic exposure, i-ray and g-ray were initially used to give patterns with broad line widths, and the fabricated semiconductor devices thereby had low capacities. However, recent technological development has allowed the use of KrF excimer laser to give patterns with dramatically finer line widths. Thereafter the technological development has continued so as to adopt ArF excimer laser having a further shorter wavelength to lithographic exposure, and this has been achieved in very recent years. Common resins, i.e., novolak or styrenic resins, have been used in exposure to KrF excimer laser. However, in exposure to ArF excimer laser, the novolak or styrenic resins have been replaced with resins containing no aromatic moieties, i.e., with alicyclic resins, because the ArF excimer laser has a further shorter wavelength of 193 nm, and resins containing aromatic moieties, such as novolak or styrenic resins, absorb the light of this wavelength. Predominant resins used in exposure to ArF excimer laser are acrylic resins. In a mechanism applied in these acrylic resins, acrylic acid has been protected by a protecting group, and upon exposure (light irradiation), an acid is generated and acts to allow the protecting group to leave, i.e., to deprotect the protected acrylic acid into carboxylic acid, and this makes the resins to be soluble in an alkali. Most of currently used protecting groups are alicyclic groups having no polar group. However, these groups, when used alone, have insufficient adhesion to a substrate and lack affinity typically for an alkaline developer, and many acrylic monomers having a polar-group-containing alicyclic skeleton as an ester group have been proposed. Among them, monomers having an alicyclic skeleton containing a lactone ring as a polar group have been highly evaluated on their functions and have been used in large numbers. A part of such monomers can be found in Patent Document 1. Independently, the use of a lactone ring as a monocyclic ester group acting as the protecting group has been proposed typically in Patent Document 2. However, such monocyclic ester group lacks the most important function necessary for resists, i.e., etching resistance, and seems to be not so widely used. Strong demands are now made on monomers having satisfactory etching resistance, because there is developed a technique called immersion lithography in which a space between the substrate and an exposure system is filled with a liquid having a high density; and this technique allows resist patterns to be finer and finer, and along with this, the resist films tend to have smaller and smaller thicknesses. In addition, strong demands are also made on resins for use in resists to have improved solubility in organic solvents, because resins containing large quantities of alicyclic acrylic esters having lactone rings are insufficient in solubility in organic solvents such as resist solvents.    Patent Document 1: Japanese Unexamined Patent Application Publication (JP-A) No. 2000-026446    Patent Document 2: Japanese Unexamined Patent Application Publication (JP-A) No. H10 (1998)-274852